[PATCH 6/7] Fix MM Auth: disallow key_seq mismatch

In auth_get_tuple_for_subscr(), add missing condition to match incoming key_seq with stored key_seq, so that re-authentication is requested for mismatching key_seqs. Add test for this issue. --- openbsc/src/libmsc/auth.c | 1 + openbsc/tests/mm_auth/mm_auth_test.c | 32 ++++++++++++++++++++++++++++++++ openbsc/tests/mm_auth/mm_auth_test.ok | 6 ++++++ 3 files changed, 39 insertions(+) diff --git a/openbsc/src/libmsc/auth.c b/openbsc/src/libmsc/auth.c index 0a8fbf4..e4d33f0 100644 --- a/openbsc/src/libmsc/auth.c +++ b/openbsc/src/libmsc/auth.c @@ -91,6 +91,7 @@ int auth_get_tuple_for_subscr(struct gsm_auth_tuple *atuple, rc = db_get_lastauthtuple_for_subscr(atuple, subscr); if ((rc == 0) && (key_seq != GSM_KEY_SEQ_INVAL) && + (key_seq == atuple->key_seq) && (atuple->use_count < 3)) { atuple->use_count++; diff --git a/openbsc/tests/mm_auth/mm_auth_test.c b/openbsc/tests/mm_auth/mm_auth_test.c index 1d65984..2b45861 100644 --- a/openbsc/tests/mm_auth/mm_auth_test.c +++ b/openbsc/tests/mm_auth/mm_auth_test.c @@ -272,6 +272,37 @@ static void test_auth_reuse() )); } +static void test_auth_reuse_key_seq_mismatch() +{ + int auth_action; + struct gsm_auth_tuple atuple = {0}; + struct gsm_subscriber subscr = {0}; + int key_seq; + + printf("\n* test_auth_reuse_key_seq_mismatch()\n"); + + /* Ki entry, auth tuple negotiated, valid+matching incoming key_seq */ + test_auth_info = default_auth_info; + test_last_auth_tuple = default_auth_tuple; + test_last_auth_tuple.key_seq = 3; + key_seq = 4; + test_last_auth_tuple.use_count = 1; + test_get_authinfo_rc = 0; + test_get_lastauthtuple_rc = 0; + auth_action = auth_get_tuple_for_subscr_verbose(&atuple, &subscr, + key_seq); + OSMO_ASSERT(auth_action == AUTH_DO_AUTH_THEN_CIPH); + OSMO_ASSERT(auth_tuple_is(&atuple, + "gsm_auth_tuple {\n" + " .use_count = 1\n" + " .key_seq = 4\n" + " .rand = 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 17 \n" + " .sres = a1 ab c6 90 \n" + " .kc = 0f 27 ed f3 ac 97 ac 00 \n" + "}\n" + )); +} + int main(void) { osmo_init_logging(&log_info); @@ -282,5 +313,6 @@ int main(void) test_auth_then_ciph1(); test_auth_then_ciph2(); test_auth_reuse(); + test_auth_reuse_key_seq_mismatch(); return 0; } diff --git a/openbsc/tests/mm_auth/mm_auth_test.ok b/openbsc/tests/mm_auth/mm_auth_test.ok index 7dedadc..9d89bfb 100644 --- a/openbsc/tests/mm_auth/mm_auth_test.ok +++ b/openbsc/tests/mm_auth/mm_auth_test.ok @@ -28,3 +28,9 @@ wrapped: db_get_authinfo_for_subscr(): rc = 0 wrapped: db_get_lastauthtuple_for_subscr(): rc = 0 wrapped: db_sync_lastauthtuple_for_subscr(): rc = 0 auth_get_tuple_for_subscr(key_seq=3) --> auth_action == AUTH_DO_CIPH + +* test_auth_reuse_key_seq_mismatch() +wrapped: db_get_authinfo_for_subscr(): rc = 0 +wrapped: db_get_lastauthtuple_for_subscr(): rc = 0 +wrapped: db_sync_lastauthtuple_for_subscr(): rc = 0 +auth_get_tuple_for_subscr(key_seq=4) --> auth_action == AUTH_DO_AUTH_THEN_CIPH -- 2.1.4